Multiannual Analysis of Epidemiological Process Manifestations as Regards Enteroviral Infection in the Khabarovsk Territory, and the Key Factors that Predetermine Aggravation of Epidemiological Situation under the Terms of Flood

Carried out has been retrospective analysis of epidemiological process manifestations as regards enteroviral infection in the Khabarovsk Region over the period of 7 years, prior to rainfall floods in 2013. Revealed is the possibility of aggravation of epidemiological situation during hydrological emergency situation. The premises are as follows: persistent due to specific climate conditions prevalent in the Khabarovsk Territory (high air and surface water temperatures, and high humidity rates) unfavorable epidemiological situation on enteroviral infections, virus-carriage in “healthy” people and extensive dissemination of enteroviruses in the water bodies of ambient environment. Moreover, widespread circulation of different enterovirus genotypes, including the isolates with high genetic similarity to the strains identified earlier in the adjoining People’s Republic of China, takes place

Genetic Relationship between Cocirculating Human Enteroviruses Species C

Recombination events between human enteroviruses (HEV) are known to occur frequently and to participate in the evolution of these viruses. In a previous study, we reported the isolation of a panel of viruses belonging to the Human enterovirus species C (HEV-C) that had been cocirculating in a small geographic area of Madagascar in 2002. This panel included type 2 vaccine-derived polioviruses (PV) that had caused several cases of acute flaccid paralysis in humans. Previous partial sequencing of the genome of these HEV-C isolates revealed considerable genetic diversity, mostly due to recombination. In the work presented herein, we carried out a more detailed characterization of the genomes of viruses from this collection. First, we determined the full VP1 sequence of 41 of these isolates of different types. These sequences were compared with those of HEV-C isolates obtained from other countries or in other contexts. The sequences of the Madagascan isolates of a given type formed specific clusters clearly differentiated from those formed by other strains of the same type isolated elsewhere. Second, we sequenced the entire genome of 10 viruses representing most of the lineages present in this panel. All but one of the genomes appeared to be mosaic assemblies of different genomic fragments generated by intra- and intertypic recombination. The location of the breakpoints suggested potential preferred genomic regions for recombination. Our results also suggest that recombination between type HEV-99 and other HEV-C may be quite rare. This first exhaustive genomic analysis of a panel of non-PV HEV-C cocirculating in a small human population highlights the high frequency of inter and intra-typic genetic recombination, constituting a widespread mechanism of genetic plasticity and continually shifting the HEV-C biodiversity

Recombination between Polioviruses and Co-Circulating Coxsackie A Viruses: Role in the Emergence of Pathogenic Vaccine-Derived Polioviruses

Ten outbreaks of poliomyelitis caused by pathogenic circulating vaccine-derived polioviruses (cVDPVs) have recently been reported in different regions of the world. Two of these outbreaks occurred in Madagascar. Most cVDPVs were recombinants of mutated poliovaccine strains and other unidentified enteroviruses of species C. We previously reported that a type 2 cVDPV isolated during an outbreak in Madagascar was co-circulating with coxsackieviruses A17 (CA17) and that sequences in the 3′ half of the cVDPV and CA17 genomes were related. The goal of this study was to investigate whether these CA17 isolates can act as recombination partners of poliovirus and subsequently to evaluate the major effects of recombination events on the phenotype of the recombinants. We first cloned the infectious cDNA of a Madagascar CA17 isolate. We then generated recombinant constructs combining the genetic material of this CA17 isolate with that of the type 2 vaccine strain and that of the type 2 cVDPV. Our results showed that poliovirus/CA17 recombinants are viable. The recombinant in which the 3′ half of the vaccine strain genome had been replaced by that of the CA17 genome yielded larger plaques and was less temperature sensitive than its parental strains. The virus in which the 3′ portion of the cVDPV genome was replaced by the 3′ half of the CA17 genome was almost as neurovirulent as the cVDPV in transgenic mice expressing the poliovirus cellular receptor gene. The co-circulation in children and genetic recombination of viruses, differing in their pathogenicity for humans and in certain other biological properties such as receptor usage, can lead to the generation of pathogenic recombinants, thus constituting an interesting model of viral evolution and emergence

Analysis of the Influence of Inductor Saturation on the Level of Electromagnetic Interference of DC/DC-converters

The results of the study on the effect of the design parameters of a nonlinear inductor on the level of electromagnetic interference generated by DC/DC converters are presented. The paper proposes models designed for the LTspice XVII environment, which allow investigating conducted interference spectra, efficiency and output voltage ripple of the converter using a nonlinear inductor model. The simulation results showed that the level of conducted interference is affected by the volume and material of the inductor core, as well as the presence of an air gap in the core. The results of measurements of conducted interference spectra at different values of the cross-sectional area of the inductor core of the DC/DC converter are presented. With the nominal cross-sectional area of the core, calculated taking into account converter output power, the study of the relationship between the level of conducted interference and the width of air gap in the inductor core is carried out. In the course of studies, using the Chan model, the influence of inductor core material on the level of interference generated by the DC/DC converter is analyzed. Analysis of the influence of the width of the air gap in the inductor core on the level of conducted interference is carried out. It is shown that air gap width should be selected taking into account inductor core material. Simulation results for a number of commonly used materials made it possible to determine the most effective one in terms of generated interference.The results obtained in the analysis of switching voltage converter operation, taking into account inductor nonlinearity, allow us to formulate recommendations to reduce the level of generated conducted interference by 4.5 to 6 dB due to the correct choice of inductor material and design parameter

Properties of Hybrid Complexes Composed of Photosynthetic Reaction Centers from the Purple Bacterium Rhodobacter sphaeroides and Quantum Dots in Lecithin Liposomes

A photosynthetic reaction center (RC) is a natural mesoscopic structure with dimensions of ~10 nm However, for creating a RC-based hybrid energy transformer it is necessary to solve some problems. First, it is necessary to obtain a high stability of photosynthetic pigment-protein complexes in vitro, because without photoprotection and repair systems they are subject to pronounced photodestruction. Second, the solar light absorption by the pigment-protein complexes of RCs is not equally efficient throughout the whole spectrum: the main absorption bands of the RC pigments are in the blue and near infrared regions of the spectrum, and it is impor- ISSN 0006-2979, Biochemistry (Moscow), 2014, Vol. 79, No. 11, pp. 1183-1191. © Pleiades Publishing, Ltd., 2014. Original Russian Text © V. E. Zagidullin, E. P. Lukashev, P. P. Knox, N. Kh. Seifullina, O. S. Sokolova, E. V. Pechnikova, H. Lokstein, V. Z. Paschenko, 2014, published in Biokhimiya, 2014, Vol. 79, No. 11, pp. 1452-1463 On-Line Papers in Press, as Manuscript BM14-145, Published on September 7, 2014. 1183 Abbreviations: BChl, bacteriochlorophyll; BPheo, bacteriopheophytin; D-D, detergent-and dialysis-based method of liposomes preparation; RC, photosynthetic reaction center; QDs, quantum dots. * To whom correspondence should be addressed. Abstract-Quantum dots (QDs) can absorb ultraviolet and long-wavelength light energy much more efficiently than natural light-harvesting proteins and transfer the excitation energy to photosynthetic reaction centers (RCs). Inclusion into liposomes of RC membrane pigment−protein complexes combined with QDs as antennae opens new opportunities for using such hybrid systems as a basis for artificial energy-transforming devices that potentially can operate with greater efficiency and stability than devices based only on biological components. RCs from Rhodobacter sphaeroides and QDs with fluorescence maximum at 530 nm (CdSe/ZnS with hydrophilic covering) were embedded in lecithin liposomes by extrusion of a solution of multilayer lipid vesicles through a polycarbonate membrane or by dialysis of lipids and proteins dispersed with excess detergent. The dimensions of the resulting hybrid systems were evaluated using dynamic light scattering and by transmission cryoelectron microscopy. The efficiency of RC and QD interaction within the liposomes was estimated using fluorescence excitation spectra of the photoactive bacteriochlorophyll of the RCs and by measuring the fluorescence decay kinetics of the QDs. The functional activity of the RCs in hybrid complexes was fully maintained, and their stability was even increased. Properties of Hybrid Complexes Composed of Photosyntheti

CURRENT POSSIBILITIES AND POTENTIAL DEVELOPMENT OF MOLECULAR ENTEROVIRUS SURVEILLANCE. EXPERIENCE OF RUSSIAN FEDERATION

Abstract. Enteroviruses are small RNA viruses, which are ubiquitous and commonly cause outbreaks with various clinical manifestations. In 2006, the Program on enterovirus surveillance was approved in the Russian Federation. Over the last years, molecular-biological and bioinformatics methods for enterovirus epidemiology studies have been developed both in Russia and worldwide. Currently, identification of enteroviruses is carried out by analyzing nucleotide sequence of the full-length VP1 genome region (ca. 900 nt). Routinely, it is sufficient to obtain a partial VP1 genome region sequence (ca. 300 bp) for enteroviruse verification in most cases; however, a more stringent type criterion of 80% sequence identity should be used compared to the 75% sequence identity cut-off for the complete VP1 genome region. Further sequence analysis may be performed by using Bayesian phylogenetic methods, which allow using molecular clock to trace outbreak emergence. Enteroviruses accumulate about 0.5–1% nucleotide substitutions per year. Therefore, a short genome fragment may be used to analyze virus phylodynamics at the level of international transfers and circulating virus variants. On a shorter timescale, a full-length VP1 genome region or a complete genome sequence are preferred for investigating molecular epidemiology, because a short sequence allows to reliably distinguish not more than 1–2 transmission events per year. Thus, determining enterovirus sequences for full-length VP1 genome region or full-genome sequence is preferred for examining viral outbreaks. It is increasingly apparent that analyzing available enterovirus nucleotide sequences reveals limitations related to uneven surveillance efficacy in various countries and short length of genome fragment measured in routine control. As a result, a proper global-scale analysis of enterovirus molecular epidemiology remains problematic. Over the last 20 years, the number of available enterovirus nucleotide sequences increased by hundred times, but understanding emergence of enterovirus infection outbreaks remains limited. Further development of enterovirus surveillance would require new methods for sewage monitoring, affordable high-throughput sequencing and harmonization of global surveillance systems